Abstract: Numerical calculation model is set up by using the strain-softening model and the temperature pattern in FLAC3D. Considering the revision in in-situ stress related to the temperature and embedding it in the calculation model in the form of a function, we discuss the stress and the characteristics of the plastic zone of irregular failure. The influence of formation temperature and rock mass thermodynamic parameters on irregular failure in deep rock mass is considered, and the characteristics of the maximum and minimum stress and the plastic zone are analyzed. The plastic zone figure of FLAC3D presents obvious irregular failure. As formation temperature and the linear expansion coefficient increase, the irregular failure in deep rock mass tends to be more serious. The greater the coefficient of linear expansion of rock is, the more it is sensitive to temperature. The influence of specific heat and thermal conductivity on irregular failure in deep rock mass is weak. The shock of the maximum minimum principal stress curve is obtained, and the relationship between the maximum shear stress and the plastic zone is similar but different to the maximum shear stress theory. There is a corresponding relationship between the outer boundary of plastic zone and the main central peak of the maximum shear stress curve, but the main central peak of the maximum shear stress curve is lag relative to the plastic zone boundary.